By Liat Clark, UK wired

An American startup is developing a self-filling water bottle that draws moisture from the atmosphere to create condensation, much like the humble beetle in the Namib Desert.

The beetle, endemic to the African Namib Desert – where there is only 1.3 cm of precipitation per year – has inspired quite a bit of proof of concept in the academic community, but this is the first time that a bottle self-filling water is offered. The beetle survives by collecting condensation from ocean breezes on the hardened shell of its wings. The shell is covered with tiny bumps that attract water (hydrophilic) at their ends and repel water (hydrophobic) at their sides. The beetle stretches and directs its wings towards the incoming sea breezes to catch the moist air; tiny droplets 15 to 20 microns in diameter eventually collect on its back and descend straight towards its mouth.

NBD Nano, made up of two biologists, an organic chemist and a mechanical engineer, builds on previous studies that built structurally superior synthetic copies of the shell. An earlier incarnation of the material was first constructed in 2006 by a team at MIT: they dipped glass or plastic substrates over and over again into charged polymer chain solutions to manipulate the surface composition. Silica nanoparticles were then added to create a rougher texture that traps water, and a Teflon-like substance sealed it. Charged polymers and nanoparticles were then layered in patterns to create contrast between the rough and porous surfaces.

NBD Nano claims to have achieved a proof of concept with its water-attracting (superhydrophilic) and water-repellent (superhydrophobic) dual bottle design, and is currently working on a prototype and seeking funding. Incredibly, the team predicted that the bottle could collect between half a liter and three liters of water per hour, depending on the local environment.

“Dry places like the Atacama Desert or the Gobi Desert don’t have access to a lot of water sources,” co-founder Miguel Galvez told the BBC. “So if we create [several] liters per day cost-effectively, you can bring it to a community of people in sub-Saharan Africa and other dry parts of the world. And if you can do it inexpensively, then you can really make an impact on the local environment. “

However, it is unlikely to be immediately used in arid environments such as the Namib, but rather on green roofs and greenhouses. It can also be used by the military, before becoming a portable, self-filling water bottle for countries with poor rainfall. The latter is “a design that may someday be achievable, although it could take years,” says NBD Nano. However, it is unlikely that it could meet all the needs of a community, from household use to cooking to farming, but it might serve as an emergency device instead.

The Namib beetle had previously inspired the 2011 Dyson International Prize winner Edward Linacre, who designed the Airdrop, an irrigation system that pumps and then cools air through underground pipes to create condensation in the airdrops. plant roots.

Source: Wired.co.uk